package com.xzcedu.mhl.dao;

import com.xzcedu.mhl.utils.JDBCUtilsByDruid;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;

/**
 * @author 徐州城
 * @version 1.0
 * 开发BasicDAO，是其他DAO的父类
 */
public class BasicDAO<T> { //泛型指定具体的类型

    private QueryRunner qr = new QueryRunner();

    //开发通用的dml方法，针对任意表
    public int update(String sql, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.update(connection, sql, parameters);
        } catch (SQLException e) {
            throw new RuntimeException(e); //将编译异常 -> 运行异常，抛出
        } finally {

            JDBCUtilsByDruid.close(null, null, connection);
        }
    }


    //返回多个对象(查询的结果是多行)，针对任意表

    /**
     * @param sql        sql语句，可以有?
     * @param clazz      传入一个类的Class对象，比如 Actor.class
     * @param parameters 传入? 的具体的值，可以是多个
     * @return 根据泛型 T ，返回对应的集合
     */
    public List<T> queryMultiply(String sql, Class<T> clazz, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.query(connection, sql, new BeanListHandler<T>(clazz), parameters);

        } catch (SQLException e) {
            throw new RuntimeException(e); //将编译异常 -> 运行异常，抛出
        } finally {

            JDBCUtilsByDruid.close(null, null, connection);
        }
    }


    //查询单行结果的通用方法
    public T querySingle(String sql, Class<T> clazz, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.query(connection, sql, new BeanHandler<T>(clazz), parameters);

        } catch (SQLException e) {
            throw new RuntimeException(e); //将编译异常 -> 运行异常，抛出
        } finally {
            JDBCUtilsByDruid.close(null, null, connection);
        }
    }


    //查询单行单列方法，即返回单值的方法
    public Object queryScalar(String sql, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.query(connection, sql, new ScalarHandler(), parameters);
        } catch (SQLException e) {
            throw new RuntimeException(e); //将编译异常 -> 运行异常，抛出
        } finally {

            JDBCUtilsByDruid.close(null, null, connection);
        }

    }

}
